MicrostripKit is a versatile microstrip tool kit app for microstrip circuit analysis and design on iPad. The app realizes various functions, including microstrip line analysis and synthesis, calculations of input impedance, reflection coefficient, and frequency response in terms of S-parameters. A Smith chart tool is also provided to aid in designing a microstrip circuit. In addition, using a novel multiple 1-D FDTD method, the app shows time-domain simulation of microstrip circuits incorporated with lumped elements, including resistors, capacitors, and inductors in parallel, as well as series connections. Several educational circuit examples are provided to help illustrate the electromagnetic wave propagation in the microstrip circuit. Fore more information, please refer to “A Mircostrip Circuit Tool Kit App with FDTD Analysis Including Lumped Elements,” IEEE Microwave Magazine, vol. 16, no. 1, pp. 74-80, 2015. (The previous 2014 version of this app is called mustripkit.)